1. Field of the Invention
The present invention relates to a valve stem seal device, and more particularly to a valve stem seal device used in a valve portion of a motor vehicle engine or a general industrial machinery.
2. Description of the Conventional Art
Conventionally, as shown in FIG. 6, there has been known a valve stem seal device structured such that a valve stem seal 700 is fixed to a valve stem guide 100 side, the valve stem seal 700 being provided with a cylindrical metallic ring 200 which is retained to an outer periphery of the valve stem guide 100, and a seal lip 400 which is integrally formed in one end side of the metallic ring 200, hermetically slides in relation to the valve stem 300 and is made of a rubbery elastic material (Japanese Patent No. 3155483 and Japanese Unexamined Patent Publication No. 2005-127147).
Further, the valve stem seal device is structured such that a projection 220 formed in a rubbery elastic material layer 210 formed in an inner peripheral surface of the metallic ring 200 is engaged with a groove 110 provided in an outer peripheral surface of the valve stem guide 100, for preventing the valve stem seal 700 from falling away from the valve stem guide 100.
However, since the projection 220 is made of the rubbery elastic material, not only a mechanical strength is not sufficient, but also a fitting and fixing force is lowered by a thermal influence and a change with time. Accordingly, in the case that a load caused by vibration or a load caused by rise of an internal pressure in the valve stem seal device is applied, not only a seal function of the valve stem seal 700 is lowered, but also there has been brought about a problem that the valve stem seal 700 falls away from the valve stem guide 100 in the worst case.